Sterilized storage container

ABSTRACT

A container lid (12) is held open by a support plate (18) carrying a chamber (20) which expands at a predetermined point in a sterilizing cycle to react against the lid, moving the plate outwardly to permit the lid to drop onto the container base. A resilient gasket (16) prevents fluid flow into the container after the lid is fallen, but permits fluid flow outwardly past the gasket when interior pressure exceeds exterior pressure. When the container is to be opened, a relief valve (60) relieves the vacuum within the container and filters air entering the container at that time.

RELATED APPLICATIONS

This application is a continuation of application Ser. No. 328,701, filed Dec. 8, 1981, which issued as U.S. Pat. No. 4,372,921 of Feb. 8, 1983 which is a continuation on application Ser. No. 115,678, filed Jan. 28, 1980 now abandoned which is a continuation-in-part of U.S. patent application, Ser. No. 895,239, filed Apr. 10, 1978, which issued as U.S. Pat. No. 4,247,517 Jan. 27, 1981, which is a continuation-in-part of U.S. patent application, Ser. No. 821,042, filed Aug. 1, 1977, which issued as U.S. Pat. No. 4,251,482 on Feb. 17, 1981, which is a continuation-in-part of U.S. patent application, Ser. No. 734,228, filed Oct. 20, 1976, which was abandoned in favor of continuation application, Ser. No. 923,359, filed July 10, 1978, which is now abandoned in favor of continuation application Ser. No. 144,068, filed Apr. 28, 1980, which issued as U.S. Pat. No. 4,349,118 on Sept. 14, 1982 application Ser. No. 734,228 being a continuation-in-part of U.S. patent application, Ser. No. 703,044, filed July 6, 1976, which issued as U.S. Pat. No. 4,196,166 on Apr. 1, 1980 which is a continuation-in-part of U.S. application, Ser. No. 640,824, filed Dec. 15, 1975, which was abandoned in favor of continuation application, Ser. No. 827,992, filed Aug. 26, 1977 which issued as U.S. Pat. No. 4,149,650 on Apr. 17, 1979.

BACKGROUND OF THE INVENTION

This invention relates to an improved system for storing items while they are being sterilized, while they are being stored awaiting use, while they are in the process of being used, and after they have been used and are waiting resterilization. The invention particularly relates to a system having an improved actuator for automatically releasing a container lid at a predetermined temperature, an improved gasket for the container and an improved relief valve for the container. The system is particularly useful in connection with the sterilization and storage of medical items, such as surgical instruments.

As explained in the above-referenced patent applications, a need exists for an improved system for sterilizing surgical instruments and other medical items in that the common method of wrapping articles in sheets, sterilizing them and then storing them while still in the sheets, is an unsatisfactory approach. Scientific studies have shown that thirty percent of the packs prepared with sheets are contaminated by bacteria at the time of use. Further, instruments in such packs using sheets are contaminated with lint.

In the most recently filed patent application referred to above, articles to be sterilized are placed in a container, and the container is placed in an autoclave with the lid held open. After the articles have been sterilized, a pressure responsive actuator automatically releases the lid and allows it to fall into a closed position wherein a resilient gasket prevents further flow into the container. The actuator utilizes an expandable chamber which responds to pressure changes to produce an actuating movement. In a preferred approach, a quantity of sterilizing fluid is captured within the chamber by means of a temperature responsive valve. Although the systems disclosed in the earlier applications are valuable approaches, further improvements have been made in connection with a production version of the system.

SUMMARY OF THE INVENTION

A support plate is mounted on the periphery of a container base, and a projection or other support means on the support plate holds the lid in open position. A bellows or other suitable expandable chamber is mounted on the support plate; and at the end of the sterilizing phase of the autoclave cycle a chamber expands against the lid to force the support means away from the lid and allow it to fall onto the base. Advantageously, the support plate may be molded as a one-piece, relatively stiff plastic member, with means on its lower end for mounting on the periphery of the container base. In a preferred approach, the support plate has a pair of projections which extend beneath the edge of the lid to hold it in open position. A thin diaphragm in the form of a bellows construction is secured to the plate so that the diaphragm in combination with the plate uniquely forms the expandable chamber. Further, the support plate is provided with an inlet nipple that extends into the expandable chamber to permit steam or other sterilizing fluid to enter the chamber during the sterilizing phase of the autoclave cycle. A heat shrinkable sleeve valve element surrounds the nipple to close the chamber during the sterilizing phase to capture a volume of fluid in the chamber.

As the lid falls onto the base, it is critical that a seal be provided to prevent further flow into the container. A resilient gasket carried by the lid is formed with a lower flap having a feathered edge which engages a mating surface in the base to provide this initial seal. As a vacuum is formed in the container either by a final vacuum in an autoclave cycle or by the cooling of the residual environment in the container, the gasket is further compressed between the lid and the base. An enlarged bead on the gasket is compressed between the lid and the base to form a second seal for the container. Thus the container contents are sealed and preserved in a sterile, lint-free environment.

Because of the excellence of the seal obtained with the gasket, a vacuum is maintained in the container for an extended period of time. Consequently, to remove the lid of the container, it is necessary to release the vacuum. This is accomplished by providing a manually operated relief valve which plugs into a hole in the lid. During this operation, air rushes into the container. Since the lid is normally removed in an area which is not totally sterile, there is a potential source of contamination. To minimize this effect, the relief valve of the invention incorporates a small filter that removes dust and most other particles in the air. When the vacuum in the container is to be relieved, it is only necessary to pull on a tab attached to the valve flange to expose the valve opening and allow air to enter.

The container is constructed to withstand atmospheric pressure when a very high vacuum exists within the container. Nevertheless, with very large containers it is desirable to provide some additional supporting structure as a safety precaution. Thus, as another feature of the invention, an instrument basket positioned in the container is arranged to support the lid. Further, the basket may be provided with a cone-shaped projection extending upwardly from its bottom wall toward the container lid, or such projection may be formed on either a lid or the base and used with or without a basket. Thus, if the lid should commence to buckle due to the pressure, the support cone will distribute the load and limit the inward movement.

SUMMARY OF THE DRAWINGS

For a more thorough understanding of the invention, refer now to the following detailed description and drawings in which:

FIG. 1 is a perspective view of the overall container showing the lid of the container held in an open position;

FIG. 2 is a side elevational view of the container of FIG. 1, partially cut away;

FIG. 3 is a side elevation of the container of FIG. 2 after the lid has fallen into closed position;

FIG. 4 is a fragmentary, perspective view of one end of the container base;

FIG. 5 is a fragmentary, cross-sectional view of the container base of FIG. 4 showing the lid and gasket positioned on the base, when the other end of the lid is held in an open position;

FIG. 6 is a perspective, exploded view of the expandable chamber actuator and a fragment of the container base illustrating the manner in which the actuator is mounted on the base;

FIG. 7 is a view like FIG. 6 but with the actuator mounted on the base and the chamber expanded;

FIG. 8 is a cross-sectional view of the expandable chamber showing the expanded position of the chamber in phantom lines;

FIG. 9 is a cross-sectional view of the inlet valve of the expandable chamber showing the valve in closed position;

FIG. 10 is a fragmentary view of the container showing the actuator in side elevation on the container base and holding the lid open showing the lid, base and gasket in cross-section;

FIG. 11 is a cross-sectional view of the gasket free form;

FIG. 12 is a cross-sectional view of the gasket mounted on a portion of the lid, also shown in cross-section;

FIG. 13 is a cross-sectional view of a portion of the lid, gasket and base with the lid in closed position on the base;

FIG. 14 is a perspective view of the relief valve for the sterilizing container;

FIG. 15 is a cross-sectional view of the valve of FIG. 14 installed in an opening in the container lid; and

FIG. 15a shows the valve with a vacuum in the container;

FIG. 16 is a perspective view on the upper side of the valve of FIG. 14 showing the valve held in open position; and

FIG. 17 is a side view partially sectionalized showing a support cone in the container basket illustrating the relation between the cone, basket cover, and the container lid.

DETAILED DESCRIPTION

Referring now to FIGS. 1 and 2, there is shown a container 10 having access means or a lid 12 closing the open upper side of a base 14, with a gasket 16 carried by the lid and extending between the base and the lid. The container illustrated has a generally oval or racetrack configuration with the container lid having a somewhat dome-shape for strength purposes. Other configurations, such as circular, could also be employed. The upper portion of the lid is shaped to mate with recesses in the container base to facilitate stacking of the containers.

One end of the lid 12 is held open by an actuator 18 which is mounted on the base 14. The actuator includes a bellows-like inflatable chamber 20 which operates to release a lid at a desired point in an autoclave sterilizing cycle, allowing the lid to drop to the position shown in FIG. 3. FIG. 2 also shows a basket 22 and cover 23 within the container for holding items to be sterilized and to add support to the container when a vacuum exists in it. One suitable material for the container is polysulfone which is sold by Union Carbide Company.

The basket includes a plurality of holes 24 spaced around the lower side wal of the basket, to permit sterilizing fluid to circulate and to allow air to escape. Also provided are a plurality of drain holes (not shown) in the basket bottom wall to permit condensation to drain from the basket. Referring to FIG. 5 it may be seen that the container base 14 includes a bottom wall 14a which slopes downwardly and outwardly to a shoulder 14b leading to a peripheral groove 15. The bottom wall 14c of the groove 15 also slopes slightly downwardly in the outward direction to insure that condensation will flow through the drain holes in the basket and drain holes 26 in the base, shown in FIG. 2. The periphery of the base includes an upwardly and outwardly sloping wall 14d terminating in a generally horizontal flange 14e.

The base is formed with protuberances 14f to help guide the lid into its proper position when it is being installed, as shown in FIG. 1, and to help prevent the lid from being improperly positioned on the base. FIG. 5 shows the condition of the gasket, lid and base on the left end of the container when the right end of the container is held in open position as shown in FIG. 1.

Referring to FIGS. 6 and 7, it may be seen that the actuator 18 includes a plate-like member 28 having on its lower end a tab 30 which snaps into a slot 32 formed in the base flange 14e on the right end of the container as shown in FIG. 1. The actuator 18 further includes a pair of projections or posts 34 which extend outwardly from the plate 28. The plate 28 is preferably formed as a one-piece plastic member formed in a single molding operation.

Referring to FIG. 10, it may be seen that the tab 30 on the plate 28 includes one or more detents 30a which require the tab 30 to be snapped into position through the slot 32 in the flange 14e. This attachment coupled with the sides of the slot 32 in the somewhat horizontal wall 31 on the plate 28 support the actuator plate in a position extending upwardly approximately as shown in somewhat cantilever fashion. As can be seen the post-like projections 34 on the support plate 28 connect to the lid 12 by extending beneath the gasket 16 on the lid. Actually, with the lid removed but with the support plate mounted on the base as shown in FIG. 10, the upper end of the support plate will move further than shown in FIG. 10 towards the lid 12. This insures that the lid is securely supported when the container is placed in an autoclave. Note from FIG. 10 that the support plate 28 extends inwardly towards the lid at its upper end as opposed to being completely vertical.

The support plate 28 provides a number of different characteristics. First, it should be sufficiently stiff and strong to support the lid and to provide the necessary reliability. In addition it should be relatively inexpensive so that it may be disposable. Molding the support plate 28 in a single operation with its multiple functions greatly contributes to this. In order to minimize the amount of material required and yet attain the necessary stiffness and flexibility, the plate may be formed with a plurality of gussets 33 extending between the horizontal wall 31 and the approximately vertical portions of the plate. Similarly, the edges of the upright portion may be thickened or ribbed to provide the necessary strength.

Referring to FIG. 8 as well as to FIG. 6, it may be seen that the expandable chamber 20 is partially formed by a portion of the support plate 28. More specifically, the upper portion of the support plate is molded with a circular recess of two different diameters. The outer portion includes a cylindrical wall 36 and an annular wall 38, which is further connected to a smaller diameter cylindrical wall 40 which is joined to a circular end wall 42. Together these walls form a cup-shaped recess.

The expandable portion of the chamber 20 is formed by separate bellows-like element 44 molded of a plastic material similar to that from which the plate 28 is molded but being of thinner cross-section and being more flexible. As can be seen the diaphragm 44 includes an outer cylindrical wall 44a connected to an annular wall 44b which mate with the walls 36 and 38 on the plate 28. These walls are joined by suitable means to form the expandible chamber 20. The diaphragm 44 further includes short cylindrical wall sections 44c, 44d and 44e with consecutively smaller diameters joined by connecting wall sections 44f and 44g. A central circular wall section 44h connected to the cylindrical wall 44e forms an end wall of the chamber. As can be seen from the phantom lines in FIG. 8, the diaphragm 44 assumes the position indicated when the chamber is fully expanded. Note that the cylindrical walls maintain their approximate configuration but are moved outwardly due to the flexibility of the connecting annular wall sections 44f and 44g.

The support plate 28 includes a tubular portion or nipple 46 which is formed integral with the wall 42 and projects into the chamber 20. The inner end of the nipple is closed but a plurality of ports 48 in the side wall of the nipple connect the chamber 20 to the space around it. The nipple 46 tapers slightly inwardly to facilitate a single molding operation for the plate 28 and the ports 48 are formed at an angle to the side wall of the nipple so that the ports may also be made during the molding operation. That is, the mold structure forming the interior of the nipple and the ports may be withdrawn from the back side of the plate 28 at the completion of a molding operation. The material forming the plate is somewhat flexible to permit such.

Positioned loosely over the nipple 46 is a cylindrical sleeve 50 made of heat-shrinkable material. Although the sleeve is relatively confined within the chamber, it may be more positively secured to the plate 42 by a small amount of adhesive on the end of the sleeve.

Referring to FIG. 11, the gasket 16 provides a critical function requiring very flexible resilient material formed in a specific design. The gasket 16 includes an upper generally cylindrical portion 16a having on its upper edge a thickened bead adding to strength. The lower end of the portion 16a is connected to the upper leg 16b with a central section which takes a generally U-shaped when installed on the lid. In addition to the leg 16b, this includes an annular wall 16c and a lower leg 16d, which in its free form shape extends somewhat downwardly. The outer end of the leg 16d is thickened to form a sealing bead 16e which leads to a thin flap 16f which tapers to a feathered lower edge. Note that there is a rather acute angle 17 between the flap 16f and the back side of the bead portion 16e.

As may be seen from FIG. 12, the gasket 16 mounts on an outwardly extending flange 12a formed on the lower end of the lid 12. The outer upper surface of the flange 12a is rounded as shown in FIG. 12 while the lower outer edge of the flange 12a is generally flat to mate with the gasket leg 16d when the lid is seated as shown in FIG. 13. The juncture between the flange 12a and the remainder of the lid 12 on the inner surface of the lid is smoothly rounded as can be seen from FIG. 12. Note also that the vertical thickness of the flange 12a is sightly greater than the wall thickness at the outer extremity of the flange. As seen from FIG. 12, positioning the gasket on the lid flange causes the gasket leg 16d to move upwardly somewhat so that the walls 16b, 16c and 16d move closer to a U-shape. The gasket assumes this configuration where ever it can hang free on the lid 12. In other words, referring to FIG. 1, the gasket would assume the position shown in FIG. 12 throughout its periphery except that the gasket on the left end of the container will appear approximately as shown in FIG. 5 and the gasket on the right end of the container in the area of the support actuator 18 will be as shown in FIG. 10.

OPERATION

When the container is first placed in the autoclave, the actuator will be in the position shown in FIGS. 1 and 10 holding the lid open and the expandable chamber 20 will be in the position shown in FIG. 8. If the particular autoclave cycle being used includes one or more preliminary vacuum phases to withdraw air from the containers, no movement of the actuator will occur, since the port 48 and the valve for the inflatable chamber 20 are open and not covered by the sleeve 50. Any pressure changes within the autoclave will be automatically applied to the interior of the chamber as well. When a high temperature sterilizing fluid such as gas or steam is applied to the autoclave, the fluid flows into the interior of the container and through the open lid into the interior of the basket through the ports 24, to displace the air and sterilize the container and the basket contents. Since the gasket 16 is positioned on the lid 12 relatively loosely, it has been found that the sterilizing fluid will also effectively sterilize the lower surfaces of the lid and the surfaces of the gasket.

The sterilizing environment applied to the container will of course also enter the chamber 20 through the ports 48. The elevated temperature of the fluid will cause the sleeve-like valve element 50 to shrink and cover the ports 48, as shown in FIG. 9. The high temperature, high pressure fluid is thus captured in the chamber. No change however occurs in the volume of the chamber during the remainder of the sterilizing phase, since temperature and pressure surrounding the chamber is essentially the same as that within it. Most autoclaves have some minor variations in temperatures and pressures during the sterilizing phase but such variations are not significant enough to cause the actuator to perform its actuating function. Thus, during the entire sterilizing phase, the lid of the container remains raised on one edge from the base such that fluid can flow freely into and out of the container. It is important that the lid be raised sufficiently to permit the sterilizing fluid to circulate freely and displace the air in the container. Preferably the lid should be raised at least a third of the height of a dome-shaped lid. It is also important that the circulation holes 24 in the basket be sized and spaced to permit the sterilizing fluid to displace the air in the basket. Condensation drains from the basket 22 through the holes in the bottom, and from the container through the drain holes 26 in the container base 14.

At the completion of the sterilizing phase of the cycle, there is an immediate pressure drop. Temperataure also drops but this is much more slowly. As the pressure drops in the autoclave, the expandable chamber 20 expands due to the fact that the pressure of the steam captured within the chamber is greater than the pressure surrounding it. Thus, the bellows-like diaphragm 44 of the chamber 20 will move to the configuration shown in phantom lines in FIG. 8 and shown in solid lines in FIG. 3 and 7. Since the central wall 44h of the diaphragm 44 is engaging the outer edge of the lid or its gasket, 16, as shown in FIG. 10, the actuator plate 28 is urged to pivot in a clockwise direction into the phantom line position shown in FIG. 10, this position also being shown in FIG. 3. The actuator moves because the resistance to movement provided by cantiliver mounting arrangement is much less than that of the lid 12. Thus, as the actuator moves, its projections or posts 34 are withdrawn from beneath the lid, allowing it to fall. Note from FIG. 8, that the wall 44h of the diaphragm 44 extends beyond the tip of the projections 34 when the bellows is fully expanded. This insures that the lid will be released. With the lid released, the actuator will move back slightly somewhat towards the upper portion of the container lid, as shown in FIG. 3, but this movement is somewhat limited while the expandable chamber is still expanded.

The lid falls into the proper position on the base and the gasket 16 assumes the approximate position shown in FIG. 13. The sloping wall 14d helps guide the lid into the peripheral groove 15 and the surfaces of the groove are smoothly curved to facilitate proper positioning of the lid. Correspondingly, the extremely flexible and resilient flap 16f on the gasket insures a proper seal on a reliable basis. In a gravity-type autoclave cycle wherein there is no final vacuum phase for withdrawing residual sterilizing environment from the autoclave, a vacuum is nevertheless formed within the container as the residual environment within the container cools and condenses, and as atmospheric pressure is introduced into the autoclave surrounding the container. The pressure differential between the interior and the exterior of the container may be quite small for a period of time in some situations such that it is important that a gasket prevent flow into the container at this time and the feathered edge of the gasket performs this function. At the same time, if the pressure within the container should be temporarily greater than the pressure on the outside of the container, the gasket feathered edge will readily permit flow out of the container, thus acting like a one-way valve. As the pressure on the interior of the container drops relative to the exterior atmospheric pressure, the lid is drawn more tightly against the base thus compressing the gasket more. This causes the bead 16e of the gasket to be further compressed between the lid and the base, becoming the primary seal for the container.

If the container is utilized in an autoclave providing a final vacuum phase, the residual environment in the autoclave is quickly withdrawn and the residual environment within the container is likewise withdrawn past the feathered edge of the gasket. When atmospheric pressure is introduced into the autoclave, the feathered edge of the gasket prevents flow into the container; and a quickly produced pressure differential between the interior and exterior of the container compresses the gasket greatly so that the bead 16e seals the container more tightly. Consequently, the container contents are sealed in essentially atmosphere free sterile environment, until the contents are to be used.

When the container is removed from the autoclave, the actuator 18 may be manually removed from the slot 32 in the container base and discarded. It is convenient to have a disposable type in a hospital environment, and the economics are such that this is a very practical approach. Alternatively, the actuator could be recycled by installing a new temperature responsive valve in the expandable chamber, or by employing a valve of a type that would recycle automatically. As one example the nipple 46 could be made as a separate component and be removeably attached to the plate, and thus could be removed to permit replacement of the valve element 50 and then reinstalled. Such an approach might be most practical, if sterilization of the container and their contents is to be performed by specialists at a central location.

The container and its contents are then transported to a storage area or to the point where the contents are needed. In use, the container is typically moved to the general area of use, but the lid of the container is actually removed somewhat remote from the actual operating or other use area in that the exterior of the container is contaminated during storage. When the lid is removed, the sterile basket on the interior protects the contents from falling dirt or other particles. The basket is carried to the actual area of use, and the cover on the basket is removed to provide access to the instruments or other items within the basket. This approach provides maximum sterility.

RELIEF VALVE

Because of the high vacuum within the container, it is impossible to remove the container lid without relieving the vacuum. For this purpose, the relief valve 60 shown in FIGS. 1, 14, 15, 15a and 16 is provided. As seen from FIG. 1, the relief valve is located in the top wall of the lid 12; however, it should be recognized that such a valve can be placed in other locations as well. Referring to FIG. 14, the valve is made of flexible resilient material as a one-piece member except for an inner filter 62. The valve includes a generally tubular projection or plug 64 which is open on its lower end and enclosed by an enlarged resilient flange 66 on its upper or outer end. A passage 68 through the projection 64 opens to a port 70 in a side wall of the projection immediately beneath the flange 66.

In use, the projection 64 is inserted through an opening in the lid 12. This operation is performed with the rigid, metal foam filter removed. The filter 62 is then installed in the lower end of the plug portion 64 as shown in FIG. 15. This not only secures the filter within the plug extending across the passage, but also helps pull the valve in a sealed condition in combination with a ring 65 on the exterior of the plug. The normal position of the valve when the container is not vacuumized is as shown in FIG. 15 with the annular edge 66a of the flange 66 against the outer surface of the lid thus preventing flow into the container through the port 70 and passage 68.

When the container lid 12 moves to its closed position, the valve 60 prevents air flow into the container; and as a vacuum is formed within the container, the exterior pressure forces most of the lower surface of the valve flange 66 against the lid. The annular relief groove 69 in the upper surface of the flange 66 and the annular groove 67 in the lower surface adjacent the plug 64 enable the flange to flatten readily. In addition, the thin upper wall 66b of the flange covering the end of the passage 68 is drawn inwardly because of the vacuum. This provides visible indication to an observer that a vacuum condition exists in a particular container.

When the vacuum is to be released to enable the container lid to be withdrawn, a tab 74 is manually pulled to lift the edge of the flange 66 away from the lid so that air may flow into the port 70 and through the passage 68 in the valve. If desired, the tab may be hooked on a tab holder 76 as shown in FIG. 16. This may be convenient in that the filter 60 is so fine that it will take several seconds for the pressure to equalize in a large container. All of the air entering the container must of course pass through the filter 62. Consequently, even though the entering air has not been subjected to high temperature sterilization, a high percentage of the dust, lint and other particles within the air are removed as the air passes through the filter. Once the container interior and exterior equalize, the lid can be lifted off of the base to provide access to the inner basket.

LID SUPPORT

Although the container 10 is constructed to withstand a high vacuum, it has been found desirable to provide further mechanical support for large containers. A preferred approach for providing such support is illustrated in FIG. 17. The basket cover 23, which is supported on its periphery by the basket base 22, is dimensioned so that its upper surface mates with the lower surface of the lid 12; and normally with a container lid tightly closed on a container base, the lid would be slightly spaced from the inner basket. However, if an overstressed condition should occur, such that the lid 12 should begin to buckle, it will engage the upper surface of the basket cover 23 to be supported thereby.

Further, with particularly large containers, the lower portion of the inner basket 22 is provided with an upwardly extending cone-shaped projection 78 that terminates near the cover 23 of the basket. The periphery of the basket cover 23 rests on the basket base 22, but it also engages or comes close to engaging the upper end of the support cone. The container lid 12 is formed with recesses that are complementarily received in the basket cover. Thus in the overstressed situation the basket cover will rest upon the upper end of the support cone 78 on the basket base, thus preventing collapse of the lid. Of course, a suitable support may be provided as a separate element, or attached to either the container lid or base, and used without a basket; or used with a modified basket which would fit with a support.

The operation of two different autoclave cycles is briefly discussed above. It is believed that this is sufficient for purposes of understanding the invention. However, if further information is desired, reference may be had to the before mentioned U.S. Pat. No. 4,247,517 or 4,251,482, both of which discuss such cycles in greater details and include a time, temperature and pressure graph of such operations.

Although the container is primarily designed for use with a steam or gas autoclave sterilizing cycle, it should be understood that it is also very useful with other sterilizing techniques. With microwave sterilizing, the container lid may be positioned on the container base in a lightly closed condition. As the contents are heated, any pressure increase within the container may vent from the container past the flexible gasket. When the container cools, a vacuum will be formed in the container, automatically pulling the lid more tightly closed on the container base.

With radiation sterilizing, which does not rely on heat, the container lid is placed on the base in a lightly closed position, and the container is then subjected to a vacuum to withdraw air from the container past the flexible gasket. When pressure around the container is again allowed to increase, the lid will be tightly compressed on the base, since the gasket will prevent a pressure increase in the container. The container is then subjected to radiation, leaving the container contents sterilized and sealed in an essentially atmosphere free environment.

The container may be used for a wide variety of items in addition to surgical instruments. If it is used solely for towels, bandages, and other such somewhat bulky items, it may be convenient to invert the container so that the lid becomes the base, and not use the basket. The side walls of the inverted lid will hold items like towels more easily than will a flat base. The expandable chamber actuator would function in the same manner as described above providing that the actuator is properly sized with respect to the lid. That is the height of the portion of the actuator that extends above the base is less than the height of the portion of the lid that extends above the base, so that the actuator would not interfere with a flat surface that supports the lid in an inverted position and extends to the area beneath the actuator. Once the container is closed, it could of course be returned to original position for storage and ease of handling. In the inverted position there would be no provision for drainage with the container illustrated; but there would be no drainage with towels. If desired the relief valve in the inverted lid may be modified to be open during the sterilizing phase and then automatically closed in response to temperature. Such a valve is described in the above application, Ser. No. 923,359, now abandoned. In addition to being a drain for condensate, a valve of this type would more importantly allow air to drain from the container as the stream or other sterilizing fluid is applied. 

We claim:
 1. An apparatus for containing items while the items are being sterilized and stored, said apparatus comprising:a container formed by a lid and a base; a support means selectively positioning said lid in an open position, wherein said lid is partially spaced from said base, or in a closed position relative to said base, said support means including a relatively stiff, plate-like member supported on a peripheral portion of said base, said member including a supporting portion which extends toward said lid so that when the lid is in said open position it rests on said support portion; and means attached to said member forming an expandable chamber for containing a fluid, said chamber positioned on said member so that expansion of said chamber urges said support portion away from said lid, when said lid is in said open position, to enable said lid to move to said closed position on said base, whereby said lid may be manually moved from its closed position to its open position in which it is supported by said support portion.
 2. The apparatus of claim 1 wherein said plate-like member includes a tab on its lower end which fits within a slot in the peripheral portion of said base for supporting the plate-like member on said base.
 3. The apparatus of claim 1 wherein said support portion comprises a pair of projections, one on each side of said expandable chamber, upon which said lid rests when said lid is in said open position.
 4. The apparatus of claim 1 wherein said base peripheral portion includes an outwardly extending flange with a slot formed therein and said support member has a tab on its lower end which fits within said slot, said tab and means on said lower end of said support member cooperate with the peripheral portion of said base so that the upper end of said support member is urged inwardly towards the lid, the upper portion of said support member being movable outwardly away from the lid by said expandable chamber due to the flexibility of the support member wherein the outward movement of said support member permits the lid to assume said closed position.
 5. The apparatus of claim 1 wherein said means forming the expandable chamber includes a flexible diaphragm which is attached to said member and together with a portion of said member forms said chamber.
 6. The apparatus of claim 5 wherein said member is molded as a one-piece plastic structure and said flexible diaphragm is molded as a one-piece element and secured to said member to form said chamber.
 7. The apparatus of claim 1 including a tubular projection on said member which extends into said chamber, said projection having a valve opening therethrough that places said chamber in fluid communication with the atmosphere surrounding the chamber, and a valve element which closes the opening into said chamber to capture a volume of fluid within the chamber.
 8. The apparatus of claim 7 wherein said valve element is temperature responsive to close said valve opening automatically after a high temperature sterilizing fluid has been applied to the container so that fluid which has entered the chamber is captured therein when said valve element closes the valve opening.
 9. An apparatus for containing items while the items are being sterilized and stored, said apparatus comprising a base member and a lid member which form a container, and a control actuator for controlling the closing of the container, the actuator comprising:a support plate having means formed thereon for mounting the support plate on one of said container forming members; flexible means secured to said plate forming an expandable chamber for containing fluid; and means formed on said plate adjacent to said expandable chamber for contacting an edge of the other container forming member thereby causing said container to assume an open position, said contacting means being located so that expansion of fluid within said chamber is utilized to move said contacting means away from said other container forming member thereby permitting said other member to fall onto said one of said members whereby said container assumes a closed position; said chamber being located so that when it expands it contacts said other member, when said container is in said open position, and pushes the support plate in a direction away from said other member to release said other member from said contacting means thereby causing said container to assume said closed position.
 10. The apparatus of claim 9 wherein:said base member is generally flat and said lid member is dome shaped with the height of the lid member being such that a substantial volume is provided for suitably receiving such bulk items as a basket of surgical instruments or bulky towels or bandages; and said lid member is said other chamber member and is supported above said base by said contacting means, when said container is in said open position, at a height which is at least one third the height of the dome shaped lid member to insure that when said container is in said open position and placed within an autoclave a sterilizing fluid applied to the interior of the autoclave will circulate into the region underneath said dome shaped lid member and displace any air from underneath the lid.
 11. The apparatus of claim 9 including a gasket positioned between said container forming members constructed such that fluid flow into the container is prevented when the container is in said closed position and the container forming members are seated on each other while fluid flow out of the container past the gasket is permitted even while the container members are seated on each other, the gasket further being constructed such that when portions of the container members are separated and then allowed to close by gravity, the gasket will seat properly to prevent further fluid flow into the container.
 12. The apparatus of claim 9 including a relief valve in one of said container forming members for relieving a vacuum within the container to permit the container to be opened, said relief valve including a filter arranged so that any air entering the container through the relief valve must pass through the filter.
 13. The apparatus of claim 9 including a basket having a bottom wall and an open top positioned in said container for receiving items to be placed within the container and a cover for mating with the basket to close the open top of the basket, the height of said basket and cover being such that the basket will support the container in the event a high vacuum is applied to the interior of the container and the size and characteristics of the container material are such that the container needs support.
 14. The apparatus of claim 13 including a cone-shaped support extending upwardly from the bottom wall of the basket and terminating at the basket cover to provide further support for said container.
 15. An apparatus for containing items while the items are being sterilized and stored, said apparatus comprising a base member and a lid member which form a container, and a control actuator for controlling the closing of the container, the actuator comprising:a support plate having means formed thereon for mounting the support plate on one of said container forming members; a diaphragm secured to said plate forming an expandable chamber for containing a fluid in combination with said support plate; means formed on said plate adjacent to said expandable chamber contacting an edge of the other container forming member thereby causing said container to assume an open position, said contacting means being located so that expansion of fluid within said chamber is utilized to move said contacting means away from said other container forming member thereby permitting said other member to fall onto said one of said members whereby said container assumes a closed position; and said actuator contacting means comprises means projecting outwardly from said plate to contact said edge of said other member and thereby cause said container to assume said open position.
 16. The apparatus of claim 15 wherein said plate is a one-piece molded plastic structure and said diaphragm is a one-piece, molded, thin, flexible bellows-type element secured at its periphery to said plate.
 17. The apparatus of claim 16 wherein said means projecting outwardly from said plate comprises a pair of projections, one on each side of said chamber.
 18. The apparatus of claim 17 wherein said mounting means comprises means on one end of said plate to support the plate in cantilever fashion; said plate being relatively stiff to support a load but being sufficiently flexible such that expansion of said chamber against a rigid surface will cause said plate to bend.
 19. The apparatus of claim 18 wherein said mounting means comprises a tab which fits within a slot in the periphery of said one of said members.
 20. An apparatus for containing items while the items are being sterilized and stored, said apparatus comprising a base member and a lid member which form a container, and a control actuator for controlling the closing of the container, the actuator comprising:a support plate having means formed thereon for mounting the support plate of one of said container forming members; a diaphragm secured to said plate forming an expandable chamber for containing a fluid in combination with said support plate; means formed on said plate adjacent to said expandable chamber for contacting an edge of the other container forming member thereby causing said container to assume an open position, said contacting means being located so that expansion of fluid within said chamber is utilized to move said contacting means away from said other container forming member thereby permitting said other member to fall onto said one of said members whereby said container assumes a closed position; and means defining a valve for controlling fluid flow out of said chamber, said valve being temperature responsive to fluid applied to the exterior of said chamber for closing the valve and capturing a quantity of said fluid within said chamber at a predetermined temperature.
 21. The apparatus of claim 20 wherein said valve comprises a nipple attached to said plate and extending into said chamber, and a heat-shrinkable valve element surrounding said nipple and controlling fluid flow through an opening in the nipple, said valve element being initially open to permit fluid flow into the chamber and being automatically shrunk and closed at a predetermined temperature to capture fluid within the chamber.
 22. An apparatus for containing items while the items are being sterilized and stored, said apparatus comprising a base member and a lid member which form a container, and a control actuator for controlling the closing of the container, the actuator comprising:a support plate having means formed thereon for mounting the support plate on one of said container forming members; flexible means secured to said support plate forming an expandable chamber for containing a fluid; and means formed on said plate adjacent to said expandable chamber for contacting an edge of the other container forming member thereby causing said container to assume an open position, said contacting means being located so that expansion of fluid within said chamber is utilized to move said contacting means away from said other container forming member thereby permitting said other member to fall onto said one of said members whereby said container assumes a closed position; said support plate is a one-piece, molded, plastic structure which includes a nipple formed integral with said plate and extending into said chamber and having a passage therethrough for providing fluid communication between the interior and exterior of said chamber.
 23. The apparatus of claim 22 wherein said passage is formed in a side wall of said nipple at an angle such that the passage may be formed during the molding operation in which the plate is formed, and including a sleeve formed of heat shrinkable material surrounding said nipple to control fluid flow through said passage.
 24. An apparatus for containing items while the items are being sterilized and stored, said apparatus comprising:a container base having means for receiving a container lid and having a flange extending outwardly from said means; a lid cooperating with said base to form a container; a support member having its lower end connected to said flange and extending upwardly adjacent said lid in cantilever fashion with means on the lower end of the support member which cooperate with said base flange so that the upper portion of the support member is urged inwardly towards said lid, said support member including a projection which extends towards said lid sufficiently far to support the lid when a side of the lid adjacent said support member is raised so that said side of the lid rests on said projection in an open position, the material and construction of said support member and base being such that the upper end of the support member may be moved away from the lid sufficiently far to withdraw said projection from beneath said lid so as to permit the lid to fall into a closed position on said base; and flexible means carried by and cooperating with said support member to form an expandable chamber, said chamber being located between the support member and the lid such that as said chamber expands it contacts said lid and pushes against the lid to move the upper end of the support member away from the lid withdrawing said projection from contact with said lid thereby allowing the lid to fall into said closed position.
 25. The apparatus of claim 24 including a flexible resilient gasket forming a seal between said base and said lid which prevents fluid flow into the container after said lid has fallen into closed position on the base.
 26. The apparatus of claim 24 including a temperature responsive valve on said support member which when open permits sterilizing environment applied to said container to enter said expandable chamber and which automatically closes in response to a predetermined temperature of said environment to capture a quantity of the environment within the chamber.
 27. The apparatus of claim 26 wherein said valve includes a nipple secured to said support member and extending into said chamber having a passage therethrough for providing fluid communication between the interior and exterior of the chamber, and said valve including a temperature responsive valve element fitting over said passage to prevent fluid flow out of the chamber after said environment has reached a predetermined temperature.
 28. The apparatus of claim 27 wherein said valve element is in the form of a sleeve surrounding the nipple, and the passage through said nipple opens through a side wall of the nipple so that the passage may be covered by said sleeve. 